KR20090017551A - System and method for delivery of precursor material - Google Patents

Abstract

The present invention relates to a method for distributing products, in particular pyrophoric, from a storage point to a use point. According to the invention, an inert gas is bubbled through the product, in particular pyrophoric, to be purified in the liquid state in order to generate a mixture, the mixture is preferably routed close to the use point, the product, in particular pyrophoric, is separated from the inert gas and from some light impurities, to generate a purified final product, in particular pyrophoric, in liquid or solid form. The purified product is supplied in a quantity just necessary to the use point, particularly when it is solidified in the heat exchanger after the transport of the mixture.

Description

Transfer system and method of precursor material {SYSTEM AND METHOD FOR DELIVERY OF PRECURSOR MATERIAL}

The present invention relates to a method for dispensing a liquid, in particular a pyrophoric product, from a storage point to a point of use, and in particular an apparatus for dispensing these products, including means for condensing / melting the purified product.

The semiconductor industry is moving towards using new products to meet the performance and miniaturization requirements of integrated circuits. These precursors can be used to deposit layers of these products in semiconductor manufacturing as well as optoelectronics. These products include in particular metals, organometallics, silicon precursors, and precursors of nitride, carbide layers derived or not derived from these products and for the production of flat screens of solar cells.

Some of these precursors, such as trimethyl aluminum (TMA) or trimethyl gallium (TMGa), dimethyl zinc (DiZ), DMAH (dimethyl aluminum hydride), are particularly flammable, i.e. special features that spontaneously ignite in contact with air Some of them also react with the water explosively.

In general, these products are widely employed using bubblers, that is, products in liquid form are transported by gases such as, for example, inert gases (nitrogen, argon, helium, etc.) available in the manufacturing process, and these bubblers Is located as close as possible to the semiconductor manufacturing equipment in the clean room. The product in liquid form is fed into a small, pre-packed bubbler reservoir that is disconnected when the interior is empty.

This operation provides a system that supplies these precursors that pose a high risk in terms of safety to surrounding facilities or in clean rooms, especially for operators who cannot wear appropriate protective equipment to handle spontaneous flammable or explosive products. This involves a number of connections and disconnections within the clean room.

When the bubbler exchange frequency is too high, one solution has been provided that can be installed in the protected area and supplied by these bubblers by a central system for dispensing liquid product.

This solution has the advantage of eliminating the need for bubbler exchange in the clean room, but requires routing of pressurized liquid between its protected central storage point and various bubblers close to the point of use.

To further protect the distribution of these liquids, various complementary methods have been developed, such as purging the line between each filled bubbler use points or using a double jacket pressurized with an inert gas around the pressurized liquid line. .

However, this method has a number of disadvantages, among which, in particular, the bubbler can only be filled continuously and asynchronously, and this overall installation has a rather high additional cost during installation of the system for distributing these precursors in the manufacturing unit. May be mentioned.

In general, the present invention relates to the distribution of a liquid product by bubbling an inert gas in a reservoir containing a liquid. The present invention is suitable for purifying a liquid, in particular a pyrophoric product, to remove at least some of its residual impurities during its transfer to the distribution line.

The present invention is directed only to the immediate or substantially direct need of a device in which a product, in particular a pyrophoric product, is safely routed to the point of use and a semiconductor or optoelectronic device, a flat screen or the like is manufactured as close as possible to the equipment. More suitable to provide the required amount of liquid.

This acts in particular to supply liquid that is less pure (and therefore less expensive) than the liquid supplied in the bubbler reservoir in normal use, while at least equal to or higher than the purity of the product normally supplied in the bubbler reservoir. Act to supply the product with It also acts to feed "electrical" grade products, i.e., products that are already very pure and of a more pure product with improved quality.

According to the invention, such products are to be purified, especially spontaneously flammable liquids (ie liquids as sold on the market, in particular spontaneously flammable) contained in this storage unit to produce a mixture of an inert gas and in particular spontaneously flammable products. Mixtures of product vapors, especially spontaneously flammable, which are dispensed from storage points (which may be central systems) by bubbling an inert gas into the product, and which are diluted in the inert gas, are no longer spontaneous (and at least volatile impurities) Remaining in this liquid). The vapor contained in the mixture is then, after the transfer of this gas mixture to an appropriate safe state over a predetermined interval (the transfer line can also be heated to prevent condensation of the liquid during this transfer), depending on the type of precursor used. Selective phase in the solid state condenses in liquid form as close as possible to the production equipment (after delivery) to recover the purified, in particular spontaneously flammable, product.

Other components of the mixture (such as impurities that are more volatile than precursors, and also inert gases, depending on the temperature and pressure conditions of the light hydrocarbon or mixture, for example) remain gaseous and the gas phase is removed from the mixture The mixture contains virtually inert gas and some of these light impurities. This is particularly important for applications related to the field of optoelectronics.

For example, since trimethyl aluminum solidifies at 15 ° C., in this case the distribution of this product generally proceeds to the liquid phase and then to the solid phase, since trimethyl gallium has a melting point of −15 ° C. It does not need to proceed to the solid phase.

A basic embodiment of the present invention is a device for separating the steam of other components of the mixture and, in particular, from the inert gas (after conveying), in particular of pyrophoric products. The vapor can be condensed or even solidified using a device that generates cold air. Since the cooling step acts from the initially contained impurities and from the inert gas, in particular to separate the spontaneously flammable product and to condense it (in liquid and / or solid form), it is necessary to cool this conveyed mixture. The use of the device clearly represents the best compromise for implementation.

Solidification is preferably preferred as long as it serves to recover almost all product vapors after passing through the phase of product recovery in liquid form. This solidification step is performed only when the temperature is compatible with the proper use of energy. (For reasonable energy costs, temperatures between -30 ° C and -40 ° C can be easily obtained.)

Then, in the case of coagulation, the solid can be melted by heating the reservoir or its wall where the product is coagulated to obtain the volume of liquid only the amount needed and directly usable by the equipment. This is one important aspect of the apparatus and method of the present invention.

The process of the invention allows the inert gas to be purified in a liquid state, in particular through a pyrophoric product, the mixture is preferably routed close to the point of use or to the second storage point, and then in particular to pyrophoric The product of is in liquid and / or solid form from at least some of the hard impurities that may be contained in the inert gas and in particular to be purified, especially in the pyrophoric product, to obtain a purified, in particular pyrophoric, product close to the point of use. Characterized in that separated. Preferably, this separation is carried out using cold air generating means, in particular for the conversion of spontaneously flammable gas products into liquid and / or solid products, particularly among the impurities contained in the impure spontaneously flammable products. Remove some (virtually).

It is used alone or in combination according to various alternatives of the method of the invention.

The product to be purified, in particular the pyrophoric product, is heated,

The mixture of the inert gas and, in particular, the product of pyrophoric heating, is heated during at least part of its routing,

The mixture is substantially heated along the entire length of its path up to the separation of the pyrophoric product and the inert gas,

The pyrophoric product of the mixture is separated from at least an inert gas using a cryogenic condensation system, a membrane and / or an adsorption system,

A cryogenic condensation system is used in which separation of the first phase occurs while the product in gaseous form is liquefied and recovered. In the second phase, the liquid product is selectively solidified,

A change from gas to liquid and / or solid phase is carried out by passing through a heat exchanger,

Cooling takes place in the heat exchanger by means of a compressor or indirect contact with the cooled heat transfer liquid using a Peltier effect device (thermoelectric cooling),

The solidified spontaneous product is melted into a purified spontaneous liquid state,

Inert gas is injected into the liquid, in particular the pyrophoric liquid, to be purified to produce a mixture of inert gas and purified liquid vapor, which can be immediately transferred to the reactor,

The liquid evaporates directly in an evaporator called a "flash" evaporator.

According to another aspect of the invention, a device for dispensing spontaneously flammable products is prepared, which is

First storage means of an initial (impurity) product to be dispensed,

Means for conveying inert gas,

Means for bubbling the inert gas into the initial product to produce a vapor of the mixture of the inert gas and in particular the pyrophoric product,

Means of transport of said mixture,

In particular at least some of the impurities have been selectively removed in order to produce a spontaneously flammable end product, in particular comprising condensation means of the spontaneously flammable product.

According to various alternatives of the present invention, the apparatus may include the following various features alone or in combination.

In particular the condensation means of the spontaneously flammable product consists of a heat exchanger in which the mixture and the heat exchange fluid flow, preferably consisting of a coil in the form of a double jacketed tube,

The heat exchanger comprises a first part in the form of a final product, in particular for liquefying spontaneously flammable products,

The heat exchanger comprises a second part, in particular for solidifying said product of spontaneously flammable,

Second storage means of said spontaneously flammable end product.

In addition, the apparatus of the present invention may include one or more of the following features.

Heating means of the first storage means of the initial product,

Heating means located in at least part of the means of transport of the mixture,

The separation of the purified, in particular spontaneously flammable, product from the other elements of the mixture comprises cryogenic cooling comprising at the top a means for removing at least some of the inert gas and the impurities constituting the mixture (non-condensable under the conditions used) Performed by means,

Dispensing means for the transport of purified products, especially spontaneously flammable, from the second storage means to the point of use (in liquid form or in a mixture with inert gas bubbling in the liquid as described above).

The invention will be better understood from the following illustrative embodiments, which are given as non-limiting examples in connection with the drawings shown.

1 is a flow diagram of a method and device of the present invention.

2 is a detailed view of the flowchart of FIG. 1.

3 shows a first exemplary embodiment of a heat exchanger configuration.

4 is an alternative to the heat exchanger of FIG. 3.

5 shows two different simplified configurations of the heat exchanger of the present invention.

6 shows another exemplary embodiment of a heat exchanger of the present invention.

1 shows a flow diagram of a dispensing method and device of the present invention.

The unit 100 contains the precursor product 120 in liquid form as is available on the market, and the reservoir (which can be heated by means 99) into which the vector gas is injected by bubbling. 170, in particular a mixture of pyrophoric product and an inert vector gas is itself connected to a line 201 where one end (top) is connected to the trap 301 and [approximately 200 wound heating resistors 40] By means of which a portion of its length is selectively heated) into the line 200, the trap 301 condensing the pyrophoric product, especially in liquid form, and then the product The product flows into reservoir 500 where it is stored for later use. Then, especially when the pyrophoric product is stored in solid form in the trap, in particular the pyrophoric product is liquefied in the trap 301 (including suitable heating means), and then the liquid is line 201. Through the reservoir 500 through. In particular, in order to obtain condensation or solidification of the pyrophoric product, the trap is passed through a heat exchanger to a refrigeration unit 400 which conducts heat transfer between the heat transfer liquid of the refrigeration unit and the vapor phase, which is a mixture of inert gas and pyrophoric vapor. Connected.

As shown in the figure, the reservoir 500 includes a system for injection vector gas bubbling in liquid, with an outlet very close to the user.

A device for generating cold air and heat, commonly referred to as a trap (301 above),

One or more Peltier effect elements, in which the flow direction can be reversed for cooling or heating (in a manner known to the person skilled in the art),

A refrigeration unit with or without a compressor, supplemented or not with any type of auxiliary heater (such as a heating resistor, induction heater, halogen, forced convection, etc.).

2 shows a detailed embodiment of the flow chart of FIG. 1.

The product vapor entrained in the vector gas enters, for example, through a valve controlled by a horizontal detector below the trap 301 (unit operating as a trap or cold trap). The liquid recovery phase can also be controlled without a level detector using a simple timer controlled by a programmable controller or microprocessor in a manner known per se.

The gas flow rate is controlled by the orifice 350 and the pressure of the gas entering the trap 301 is controlled in the bubbler. Gas phase flow controllers may also be used. The steam enters the trap through heat exchanger 320, which can take any form known to those skilled in the art (tubes and shells, double tubes, plate heat exchangers, etc.). This heat exchanger 320 has a dual function, where the first function is to liquefy and solidify the vapor entrained in the vector gas (when the precursor has a suitable freezing point, ie not too low), and the second function is to equip the It is to allow melting of the solids formed in the heat exchanger into the previous phase to recover the volume of liquid directly usable by 500.

An important advantage of the present invention is that only one fluid is used to provide the cold air necessary for the first function (solidification) and the heat required for the second function (preferably melting of the solid to obtain a liquid). In general, this is sufficient to shut down the compressor 430 to obtain melting of the solid product (even without circulation of any “hot” heat transfer liquid).

This is the operation of the refrigeration unit, either without a capillary expansion device or pressure reducer 410 or with a capillary expansion device or pressure reducer 410 (when valve 421 is closed and valve 422 is opened), respectively. Is made possible by the design of the refrigeration unit 400 comprising two valves 421, 422.

The refrigeration unit then solidifies the steam when the capillary or pressure reducer is in use, thereby melting the solid when the latter is avoided by connecting the compressor 440 directly through the valve 421 to the heat exchanger 320. Compressor 440 and heat exchanger 430 may use atmosphere, water, or any other fluid to cool the gas at the compressor outlet.

The present invention can be easily incorporated into current process equipment, and the design of the trap 300 can be easily incorporated into the product supply unit of the equipment available to the semiconductor manufacturing unit, while the refrigeration unit is a trap 300 It has the advantage that it can be offset and simply connected by a line for transporting the heat transfer liquid in contact with it.

Preferably, the pipe from which the product can solidify in the heat exchanger system has a diameter of at least 0.5 mm to prevent rapid blockage during solidification.

3-6 illustrate various alternative embodiments of heat exchanger 320 provided as a non-limiting example. Obviously, many alternatives can be suggested by those skilled in the art, but are within the structure of the present invention as defined above.

FIG. 3 shows a coil 39 fed to the base through lines 200 and 42 by a mixture of an inert gas and spontaneous vapor, which mixture shows the product of spontaneously flammable in line 43. Rises through line 42 inside coil 39 with double jackets 43 and 48 respectively flowing (preferably generally countercurrent) heat transfer fluid 44 which condenses and optionally solidifies, Vector gas and non-condensable impurities escape through 45 at the top. When this line 43 is filled with the product in solid form, the flow of cooling fluid is stopped, in particular to gradually liquefy the pyrophoric product and replaced by the flow of heating fluid, and then the same line 43 After flowing through, it continues to flow down through lines 42 and 41, for example to be stored in means 500 for storing purified liquid. Purified liquid may also be recovered and stored in reservoir 499 fitted with horizontal detector 498 to allow for injection of liquid into storage unit 501 via valves 497 and 201. do. In particular, in order to accelerate and improve the condensation of the pyrophoric product, it can be bubbled at the same time as it arrives via line 496 in reservoir 499 (as shown in FIG. 2), thereby allowing liquid and Some of the vapors present in the mixture are already condensed upon contact with.

FIG. 4 shows a system similar to the system of FIG. 3, but with an upper portion representing precursor solidification and melting regions and a lower portion simply vapor condensation region depending on the type of heat exchanger fluid used. The mixture inlet line 200 is heated (optionally) using a heating resistor, heating strip, and the like 40. Line 200 exits on one hand into line 41 (where the purified liquid flows down) and on the other hand into line 42 through which the liquid / vapor mixture flows. Nevertheless, this line, which is not enclosed by the cooling fluid, is already cooled (indirectly by conduction) due to the line 43 continuing above it and cooling itself. The vapor condenses to liquid in this portion of line 42. In some of the lines 43, the heat transfer liquid 44 flowing in the outer jacket 48 allows condensation and / or solidification of the pyrophoric liquid inner 43. The heat transfer fluid here flows countercurrently to the mixture (also a flow is also possible), while the vector gas (here inert gas) and optionally impurities are removed at 45, the upper end of 43. In particular after selective solidification in line 43 of spontaneously flammable product, the product is liquefied by circulating a sufficiently hot heat transfer liquid in jacket 48.

5 shows one alternative system of the system described above, wherein like elements have the same reference numerals as described above.

In FIG. 5A, the heat transfer fluid is transferred from the bottom and removed at the top of the heat exchanger after heat exchange, while steam and inert gas are injected down at the top of the heat exchanger, and the liquid is recovered at the bottom of the heat exchanger after melting. On the other hand, the vector gas is discharged through the top.

In FIG. 5B, the system is virtually identical except for the vapor and vector gas injected through the bottom, but the heat exchange fluid is injected from the top down.

In the unit of FIG. 5, the heat exchangers can be much smaller than in FIG. 4 due to the arrangement of pipes 43 parallel to each other and connected to each other at their lower and upper parts.

FIG. 6 is yet another embodiment of the heat exchanger of the invention, comprising a solidification and melting zone of the pyrophoric product (plate heat exchanger) and a vapor condensation zone at the bottom (similar to the heat exchanger of FIG. 4). Alternative embodiments are shown. This system is similar to the system described in FIG. 4 except for a heat exchanger operating with the system of FIG. 5B. The same elements as the elements in the foregoing figures have the same reference numerals. Mixture supply line 200 is also heated using heating sleeve 40.

Clearly, the present invention also extends to alternatives in which the "initial" liquid and the "final" liquid have substantially the same purity. One of the important points of the present invention is the transfer of liquids, in particular spontaneously flammable products, from one point to another under very improved safety conditions as compared to the conventional conditions for conveying these liquids and generally of the "final" product. It is in the fact that it improves purity.

Claims (23)

A method of dispensing a liquid, in particular a pyrophoric product, from a storage point to a point of use, The inert gas is bubbled through the product in the liquid state to produce a mixture of the inert gas and the vapor of the product, the mixture is preferably routed close to the point of use or the second storage point and the product is subjected to its condensation. Separated from the gas mixture by means of at least some of the initially contained in the inert gas and the liquid product to be purified, in particular light impurities, in the form of exhaust gas. The method of claim 1, wherein the product to be purified is heated. The method of claim 1 or 2, wherein the mixture of inert gas and product vapor is heated during at least a portion of its routing. 4. The method of claim 3, wherein the mixture is heated substantially along the entire length of its path until separation of the product and the inert gas. 5. The method of claim 1, wherein the product contained in the gas mixture is separated from at least an inert gas using a cryogenic condensation system, a membrane and / or an adsorption system. 6. A method according to claim 5, wherein a cryogenic condensation system is used and the separation takes place initially in the first phase, during which the gaseous, in particular spontaneously flammable, product is liquefied and recovered. 7. A method according to claim 6, wherein the liquid, in particular the pyrophoric product, is solidified. 8. The method of claim 6 or 7, wherein the change from gas phase to liquid phase and / or solid phase is carried out by a path through a heat exchanger. The method of claim 8, wherein the cooling in the heat exchanger occurs by indirect contact with the heat transfer liquid cooled using a compressor. 10. The method of any one of the preceding claims, wherein the solidified pyrophoric product is melted in a purified pyrophoric liquid state. The method of claim 10, wherein the inert gas is injected into the purified spontaneous liquid to produce a mixture of inert gas and purified spontaneous liquid that can be immediately transferred to the reactor. The purified liquid of claim 1, wherein the purified liquid is recovered and stored in a reservoir, wherein condensation of the product is accelerated and improved by bubbling a gaseous product through the purified liquid in the reservoir. Product distribution method. In the dispensing device of the product of the liquid precursor type, First storage means of initial product to be dispensed, An inert gas transfer means, Means for bubbling an inert gas into the initial product to produce a vapor of the mixture of the inert gas and the product; Means for transporting said mixture, And a condensation means of the product, wherein at least some of the impurities have been removed to produce the final product. 14. The product dispensing device according to claim 13, wherein the product condensing means is a heat exchanger through which the mixture and the heat transfer fluid flow, preferably consisting of a coil in the form of a double jacketed tube. 15. The product distribution device of claim 14 wherein the heat exchanger comprises a portion for liquefying the product in the form of a final product. The heat exchanger of claim 13, wherein the heat exchanger comprises a portion for collecting the final product, and the vapor mixture of the inert gas and the product passes through a portion of the collected final product to assist in liquefaction of the product. Product distribution device, characterized in that bubbling. 17. A product distribution apparatus according to any one of claims 13 to 16, wherein the heat exchanger comprises a second portion for solidifying the product. 18. The product distribution device according to any one of claims 13 to 17, wherein the product distribution device comprises a second storage means of the final product. 19. A product dispensing device according to any one of claims 13 to 18, wherein the product dispensing device comprises means for heating a first storage means of the initial product. 20. The product dispensing device according to any one of claims 13 to 19, wherein the product dispensing device comprises heating means located on at least a portion of the transport means of the mixture. The product of claim 13, wherein the product is separated from the other elements of the mixture by cryogenic cooling means comprising means for removing at least some of the inert gas and the fluorinated gas that forms the mixture thereon. Product distribution device, characterized in that. 22. A product dispensing device according to any one of claims 13 to 21, wherein the product dispensing device comprises dispensing means for conveying the purified product. Use of a heat exchanger to purify a product that is particularly pyrophoric in proximity to the point of use.

Images